Effects of fire exclusion: Kendall and Keane [108] state "whitebark pine will continue to decline if fire is not allowed to periodically set back the successional clock." Secondary succession, accelerated by white pine blister rust and bark beetle outbreaks, results in rapid replacement of whitebark pine by shade-tolerant, fire-sensitive species such as subalpine fir and mountain hemlock. Without burning, genetically valuable seed produced by blister-rust resistant whitebark pine is wasted: no new openings are created where Clark's nutcracker can cache seed and seedlings can establish [97]. Based upon fire records from the U.S. Forest Service's Northern Region, Arno [12] estimated that less than one-half of 1% of the seral whitebark pine type had burned in 1970-1985. At that rate, he calculated a theoretical fire-return interval of 3,000+ years. Arno and other fire researchers caution that in reality, wildfire inevitably returns to fire-prone ecosystems [38]. Fuel build-ups resulting from long-term fire exclusion dictate that when fire does return, it burns more acreage at greater severity than was historical. Estimated loss of whitebark pine from the 1988 Yellowstone fires was 30% of cone-producing stands in the north of the Park, and 12% in the east. Total reduction of whitebark pine cover was estimated at 54% [111].

Wilderness: Across its range, the proportion of whitebark pine habitat that falls within Wilderness boundaries is greater than that of nearly any other tree species [187]. Whitebark pine in Wilderness Areas is not immune to decline: Kendall and Arno [107] estimated that as of 1990, 90% of whitebark pine in Glacier National Park, much of it in wilderness boundaries, had died from white pine blister rust. Fire management of whitebark pine is particularly problematic in small Wilderness Areas, where management-ignited fires are seldom an option [101,163]. Yet conservation of whitebark pine may be impossible without reintroduction of fire to Wilderness Areas [109]. Since firelines in Wilderness areas are costly, damaging, difficult to construct in remote areas, and often in violation of the Wilderness Act, wilderness fires for resource benefit present the best management option [97]. As of this writing (2002), studies are underway to determine fire histories and explore management options in small, isolated Wilderness Areas [163]. Renkin and Despain [178] summarized a 17-year trend (1972-1988) of fire occurrence under the prescribed natural fire program in Yellowstone National Park. They found that the high moisture levels in whitebark pine ecosystems did not favor crown fires in most years (1988 being an exception), and fire occurrence was less than expected (based on amount of unburned area available) in whitebark pine communities. In mixed-conifer forests where whitebark pine was a component of the vegetation, fire occurrence was greater than expected in subalpine fir-Engelmann spruce and old-growth lodgepole pine with a subalpine fir-Engelmann spruce understory, and less than expected in seral lodgepole pine. Keane [97] states "the most important management action for conserving and maintaining vital whitebark pine ecosystems is to allow fires to burn in wilderness areas and play a more natural role in the ecosystem."

Restoring whitebark pine with fire: Long-term outlook for whitebark pine is not without hope, but restoring whitebark pine ecosystems cannot be accomplished without returning fire to subalpine landscapes. Keane and Arno [100] state "maintenance of native FIRE REGIMES is the single most important management action to ensure conservation of whitebark pine." Whitebark pine will continue to decline in the short term, but natural selection will probably increase genetic blister-rust resistance in whitebark pine populations [108,198]. It is also likely that future disturbances, particularly large fires and mountain pine beetle attacks, will kill many of these genetically valuable trees. Despite the dangers of landscape-level fire to whitebark pine populations, returning fire to the landscape is best way to restore whitebark pine. Kendall and Keane [108] state "It is important to note that fire exclusion has a far greater negative than positive consequence for whitebark pine. In the absence of fire, atypical amounts of fuel accumulate that foster more fires that are lethal to mature whitebark pine trees." Reintroduction of stand-replacing fire fosters whitebark pine regeneration by providing open sites suitable for Clark's nutcracker caching and seedling establishment. It also reduces impacts of mountain pine beetle infestations by creating mosaics of mutiaged stands that are less conducive to beetle epidemics [78]. It is encouraging that 40% of the progeny of healthy trees in stands otherwise heavily infested with blister rust show some genetic resistance to blister rust [84]. Without intervention, it is likely that the small proportion of whitebark pine resistant to white pine blister rust will be killed in stand-replacement fires before they can reproduce [108].

Management-ignited fires can be used for fire hazard reduction and whitebark pine restoration treatments [37]. Fire researchers emphasize that it is less important to reconstruct historic stand structures than to reintroduce fire to whitebark pine ecosystems. It is crucial to create open sites that are favorable for Clark's nutcracker caching and growth of natural and artificial regeneration. Six Demonstration Areas have been established in the Selway-Bitterroot Wilderness Complex of Idaho and Montana as part of the Restoring Whitebark Pine Ecosystems Project. Ongoing restoration treatments include prescribed fire and silvicultural cuttings. Since the research is ongoing, conclusions and recommendations are based on limited data, and further suggestions will be forthcoming as the project continues [100].

Large, stand-replacement fires are not recommended in areas where whitebark pine is in severe decline (for example, northern Idaho and northwestern Montana). Small-scale prescribed burning is recommended; otherwise, natural whitebark pine regeneration will be extremely slow [210]. Prescribed burning is best conducted in fall, after an early frost (<25oF (-4oC)) kills herbaceous plants and shrub foliage. Such foliage quickly cures and can propagate fire. In other seasons whitebark pine ecosystems are usually too wet to burn, or in extreme fire years, downslope vegetation is so dry that spotting may ignite fire in lower elevations. Aids for conducting stand inventories, prioritizing whitebark pine habitat for prescribed fire, designing and implementing treatments, and posttreatment monitoring and available [100]. Follow-up thinning treatments, especially of subalpine fir, are usually needed to encourage whitebark pine growth [210]. Augmenting natural regeneration with blister-rust resistant seed sources is recommended in areas where whitebark pine seed sources are absent or greatly reduced [84,210].

Unfortunately, restoration treatments may increase bark beetle predation on whitebark pine. On the Beaver Ridge Demonstration Area in northern Idaho, Six [190] found that Pityogenes fossifrons beetles were the most serious posttreatment pest species: they preferred young, apparently healthy whitebark pine in Clark's nutcracker openings, but also attacked a few fire-damaged mature trees. Ips spp. colonized slash heavily and attacked a few fire-damaged mature trees, but mostly left healthy trees alone. Mountain pine beetle numbers, which are rising in the study area, rose on the treatment sites but did not significantly respond to treatments. To reduce Pityogenes fossifrons infestation, Six [190] recommended spraying high-value whitebark pine in Clark's nutcracker openings with carbaryl for 2 posttreatment years (refer to Fire Case Studies).

Fuels: Information on tree biomass is useful in determining fuel loads and predicting potential fire behavior. Moeur [155] provides a model for estimating crown widths and foliage weights of whitebark pine and other northern Rocky Mountain conifers. Regression equations [35,36] and tables [193] are available for estimating whole-tree weight and weights of boles, branches, branchwood with foliage, and live and dead crowns of whitebark pine and other western conifers. Van Wagtendonk and others [220,221,222] provide models for calculating weight, depth, heat content, and other fuel properties of whitebark pine and other Sierra Nevada conifers.